Polarization switches are frequently used to temporally encode stereoscopic imagery for single-projector 3D projection display. An example is the ZScreen, which may include a neutral linear input polarizer, followed by alternately engaged liquid crystal pi-cells. As the output from many projector models is substantially unpolarized, such as those based on the Texas Instruments DLP microdisplay, more than half of the energy is absorbed by the input polarizer of the polarization switch. This energy is dissipated in the optical assembly, resulting in localized heating. The polarization switch is usually assembled using optical adhesives to eliminated air-glass interfaces that produce light loss and degradation in performance (e.g. contrast and transmitted wavefront distortion). Localized heating in such an assembly causes a distribution in strain, usually resulting in significant birefringence that degrades performance. In 3D display, this is manifested as a loss in the stereo contrast ratio (SCR).